douxing1353 2009-07-20 16:12

# PHP逻辑if语句

I have this code:

``````\$distance= -1 ;//default
//distance calc
if(\$dgalaxy = \$galaxy){
if((\$dx = \$x) && (\$dy = \$y))
{
//inter planitary currently unknown formula
}else{
\$distance = round(Sqrt(pow((\$dx-\$x),2)+pow((\$dy-\$y),2)));//interstllar
}
}else{//intergalatic
if (\$galaxy < \$dgalaxy){
\$distance = (((9-fmod(\$galaxy,10))*200)+2000+(fmod(\$dgalaxy,10)*200));//anti clockwise galactic
}else{
\$distance = (((fmod(\$galaxy,10))*200)+2000+(fmod(9-\$dgalaxy,10)*200));//clockwise galactic
}
}
``````

It should return a value for each calculation except for the inter planetary clause. for interstellar (when (\$dgalaxy = \$galaxy) and the x,y coordinates differ) this runs the interstellar formula and this works fine.

But, when \$dgalaxy != \$galaxy, it returns with -1 which means that it is not running either of the galactic distance calculations!

What have I done wrong and how can I fix it?

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#### 3条回答默认 最新

• dtdvlazd56637 2009-07-20 16:14
关注

`\$dgalaxy = \$galaxy` is an assignment not a comparison. Use `==`.

Ditto elsewhere.

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